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The influence of fibrous elastomer structure and porosity on matrix organization.

Ifkovits JL, Wu K, Mauck RL, Burdick JA - PLoS ONE (2010)

Bottom Line: However, all scaffolds were completely populated with cells at 4 weeks post-implantation.An increase in the amount of collagen was observed for CO scaffolds and enhanced alignment of the nascent collagen was observed for AL and CO scaffolds compared to NA scaffolds.Thus, these results indicate that the scaffold architecture and porosity are important considerations in controlling tissue formation.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

ABSTRACT
Fibrous scaffolds are finding wide use in the field of tissue engineering, as they can be designed to mimic many native tissue properties and structures (e.g., cardiac tissue, meniscus). The influence of fiber alignment and scaffold architecture on cellular interactions and matrix organization was the focus of this study. Three scaffolds were fabricated from the photocrosslinkable elastomer poly(glycerol sebacate) (PGS), with changes in fiber alignment (non-aligned (NA) versus aligned (AL)) and the introduction of a PEO sacrificial polymer population to the AL scaffold (composite (CO)). PEO removal led to an increase in scaffold porosity and maintenance of scaffold anisotropy, as evident through visualization, mechanical testing, and mass loss studies. Hydrated scaffolds possessed moduli that ranged between ∼3-240 kPa, failing within the range of properties (<300 kPa) appropriate for soft tissue engineering. CO scaffolds were completely degraded as early as 16 days, whereas NA and AL scaffolds had ∼90% mass loss after 21 days when monitored in vitro. Neonatal cardiomyocytes, used as a representative cell type, that were seeded onto the scaffolds maintained their viability and aligned along the surface of the AL and CO fibers. When implanted subcutaneously in rats, a model that is commonly used to investigate in vivo tissue responses to biomaterials, CO scaffolds were completely integrated at 2 weeks, whereas ∼13% and ∼16% of the NA and AL scaffolds, respectively remained acellular. However, all scaffolds were completely populated with cells at 4 weeks post-implantation. Polarized light microscopy was used to evaluate the collagen elaboration and orientation within the scaffold. An increase in the amount of collagen was observed for CO scaffolds and enhanced alignment of the nascent collagen was observed for AL and CO scaffolds compared to NA scaffolds. Thus, these results indicate that the scaffold architecture and porosity are important considerations in controlling tissue formation.

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Trichrome stained images of subcutaneous implant samples at 2, 3, and 4 weeks post-implantation.Images were collected for NA (A, D, G), AL (B, E, H), and CO (C, F, I) samples at 2 (A–C), 3 (D–F), and 4 (G–I) weeks post implantation to evaluate integration. S denotes the scaffold region. Scale bar = 50 µm.
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pone-0015717-g006: Trichrome stained images of subcutaneous implant samples at 2, 3, and 4 weeks post-implantation.Images were collected for NA (A, D, G), AL (B, E, H), and CO (C, F, I) samples at 2 (A–C), 3 (D–F), and 4 (G–I) weeks post implantation to evaluate integration. S denotes the scaffold region. Scale bar = 50 µm.

Mentions: Electrospun scaffolds were processed for PEO removal and sterilization prior to implantation into dorsal subcutaneous pockets in rats. Samples were collected at 2, 3, and 4 weeks after implantation and processed using standard histological techniques. Complete integration of the CO scaffolds was observed as early as 2 weeks following implantation (Figure 6C). However, 13.4±7.4% and 16.3±10.8% of free (acellular) scaffold remained for NA and AL scaffolds at 2 weeks, respectively (Figure 6A, B). Similar observations were made when scaffolds were observed at three weeks post-implantation (Figure 6D–F), where 2.1±3.6% and 3.3±5.7% of free scaffold remained for NA and AL scaffolds, respectively (Figure 6.6D, E). Complete integration was observed at 4 weeks for all groups.


The influence of fibrous elastomer structure and porosity on matrix organization.

Ifkovits JL, Wu K, Mauck RL, Burdick JA - PLoS ONE (2010)

Trichrome stained images of subcutaneous implant samples at 2, 3, and 4 weeks post-implantation.Images were collected for NA (A, D, G), AL (B, E, H), and CO (C, F, I) samples at 2 (A–C), 3 (D–F), and 4 (G–I) weeks post implantation to evaluate integration. S denotes the scaffold region. Scale bar = 50 µm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3008724&req=5

pone-0015717-g006: Trichrome stained images of subcutaneous implant samples at 2, 3, and 4 weeks post-implantation.Images were collected for NA (A, D, G), AL (B, E, H), and CO (C, F, I) samples at 2 (A–C), 3 (D–F), and 4 (G–I) weeks post implantation to evaluate integration. S denotes the scaffold region. Scale bar = 50 µm.
Mentions: Electrospun scaffolds were processed for PEO removal and sterilization prior to implantation into dorsal subcutaneous pockets in rats. Samples were collected at 2, 3, and 4 weeks after implantation and processed using standard histological techniques. Complete integration of the CO scaffolds was observed as early as 2 weeks following implantation (Figure 6C). However, 13.4±7.4% and 16.3±10.8% of free (acellular) scaffold remained for NA and AL scaffolds at 2 weeks, respectively (Figure 6A, B). Similar observations were made when scaffolds were observed at three weeks post-implantation (Figure 6D–F), where 2.1±3.6% and 3.3±5.7% of free scaffold remained for NA and AL scaffolds, respectively (Figure 6.6D, E). Complete integration was observed at 4 weeks for all groups.

Bottom Line: However, all scaffolds were completely populated with cells at 4 weeks post-implantation.An increase in the amount of collagen was observed for CO scaffolds and enhanced alignment of the nascent collagen was observed for AL and CO scaffolds compared to NA scaffolds.Thus, these results indicate that the scaffold architecture and porosity are important considerations in controlling tissue formation.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

ABSTRACT
Fibrous scaffolds are finding wide use in the field of tissue engineering, as they can be designed to mimic many native tissue properties and structures (e.g., cardiac tissue, meniscus). The influence of fiber alignment and scaffold architecture on cellular interactions and matrix organization was the focus of this study. Three scaffolds were fabricated from the photocrosslinkable elastomer poly(glycerol sebacate) (PGS), with changes in fiber alignment (non-aligned (NA) versus aligned (AL)) and the introduction of a PEO sacrificial polymer population to the AL scaffold (composite (CO)). PEO removal led to an increase in scaffold porosity and maintenance of scaffold anisotropy, as evident through visualization, mechanical testing, and mass loss studies. Hydrated scaffolds possessed moduli that ranged between ∼3-240 kPa, failing within the range of properties (<300 kPa) appropriate for soft tissue engineering. CO scaffolds were completely degraded as early as 16 days, whereas NA and AL scaffolds had ∼90% mass loss after 21 days when monitored in vitro. Neonatal cardiomyocytes, used as a representative cell type, that were seeded onto the scaffolds maintained their viability and aligned along the surface of the AL and CO fibers. When implanted subcutaneously in rats, a model that is commonly used to investigate in vivo tissue responses to biomaterials, CO scaffolds were completely integrated at 2 weeks, whereas ∼13% and ∼16% of the NA and AL scaffolds, respectively remained acellular. However, all scaffolds were completely populated with cells at 4 weeks post-implantation. Polarized light microscopy was used to evaluate the collagen elaboration and orientation within the scaffold. An increase in the amount of collagen was observed for CO scaffolds and enhanced alignment of the nascent collagen was observed for AL and CO scaffolds compared to NA scaffolds. Thus, these results indicate that the scaffold architecture and porosity are important considerations in controlling tissue formation.

Show MeSH
Related in: MedlinePlus